drown verb
1 Error: Nobody knows why the ship drowned.
->Nobody know why the ship sank.
See note at SINK
2 Error: The boy was nearly drown.
->The boy was drowning.
Error: A man jumped into the river to save her from being drown.
->
A man jumped into the river to save her from drowning.

drown (verb) = die by being under the water and unable to breathe:
‘Help him! He’s drowning!’
‘The lifeguard got to him too late. He had already drowned.’
 ‘She keeps away from the water because she’s afraid of drowning.’